--- lsof_4.87_src.org/dialects/linux/dsock.c
+++ lsof_4.87_src/dialects/linux/dsock.c
@@ -35,10 +35,9 @@
 static char *rcsid = "$Id: dsock.c,v 1.39 2013/01/02 17:02:36 abe Exp $";
 #endif
 
-
+#include <netinet/tcp.h>
 #include "lsof.h"
 #include <sys/xattr.h>
-
 
 /*
  * Local definitions
